Development of Adult T-Cell Leukemia/Lymphoma During Treatment with PD-L1 Inhibitor for Lung Cancer

Advancements in immunotherapy, the phenomenon of hyperprogression in cancer patients, have garnered increasing attention. We herein report a case of acute adult T-cell leukemia/lymphoma (ATL) that developed after administration of the programmed death-ligand1 inhibitor durvalumab in a patient with lung cancer. Although the patient was a carrier of human T-cell leukemia virus type 1 (HTLV-1), this was unknown prior to durvalumab treatment. HTLV-1 bZIP factor was detected in formalin-fixed lymph node tissue, confirming the diagnosis of ATL. Our findings suggest a potential association between immune checkpoint inhibition and ATL development in HTLV-1 carriers.